Thin multi-layer paneling structure

ABSTRACT

The invention relates to a multi-layer paneling structure having a high gloss cap and second layer of high impact resistance thermoplastic polymer or composites for exterior and interior paneling applications where chemical resistance and/or scratch resistance is desired. The invention also relates to a high gloss, multi-layer panel that can easily be repaired, once marred, to return the surface gloss to at least 90% of the original surface gloss. The invention further relates to articles made with the multi-layer paneling structure of the invention. The multi-layer structure can be used alone, or can be very thin and used as a replacement for an undercoating and coating on an article, such as a metal car part.

FIELD OF THE INVENTION

The invention relates to a multi-layer paneling structure having a highgloss first layer cap and a second layer of high impact resistancethermoplastic polymer or composites for exterior and interior panelingapplications where chemical resistance and/or scratch resistance isdesired.

The invention also relates to a high gloss, multi-layer panel that canbe easily repaired, once marred, to return the surface gloss to at least90% of the original surface gloss.

The invention further relates to articles made with the multi-layerpaneling structure of the invention. The multi-layer structure can beused alone, or can be very thin and used as a replacement for anundercoating and coating on an article, such as a metal car part.

BACKGROUND OF THE INVENTION

High gloss finishes are appealing, and are desired in many articles,including car interiors and exteriors, as well as in sports equipment,and lawn and garden equipment. One problem with typical gloss coatingsand paints, is that the surface gloss layer is easily damaged due toscratching, marring and chemical exposure. Once marred, the thin surfacecoating is difficult to repair. Additionally, many coatings involve theuse of volatile organic solvents which can cause health and/orenvironmental damage.

Certain structural plastics, such as high impact polystyrene (HIPS),acrylonitrile/butadiene/styrene (ABS) resins, poly(vinyl chloride)(PVC)resins, and the like, exhibit attractive mechanical properties whenextruded, molded, or formed into various articles of manufacture.Although these structural plastics are strong, tough and relativelyinexpensive, the properties of their exposed surfaces are less thanideal. They are easily degraded by light; can be easily scratched; andare eroded by common solvents.

A common practice in the industry to apply another resinous materialover the structural plastic to protect the underlying structuralmaterial and provide a surface that can withstand abuse associated withthe use environment. Such surfacing materials are called “capstocks”.

The capstock is generally much thinner than the structural plastic,typically being about 10% to about 25% of the total thickness of thecomposite comprising the capstock and structural plastic plies. Forexample, the thickness of the capstock can be about 0.01 mm to 0.8 mm,preferably 0.0127 mm to 0.65 mm, and more preferably from 0.04 mm to0.38 mm whereas the thickness of the structural plastic ply can be about1.0 to about 10 mm.

As a class, acrylic resins, known for their excellent opticalcharacteristics, resistance to degradation by sunlight, hardness,inertness to water and common chemicals, durability, and toughness, arecapstocks of choice for various structural plastics, such as ABS sheet.The mechanical properties of the capstock generally are secondary tothose of the structural plastic, but it is important that the capstocknot adversely affect the mechanical properties of the composite.

Typical acrylic capstock materials, such as Arkema's SOLARKOTE® resinsare described in U.S. Pat. No. 6,852,405. These capstock materials aregenerally impact modified. A problem with impact modified single acrylicsheet, is that the impact modification diminishes both the gloss, andthe chemical resistance of the cap layer.

Capstocks can be cross-linked to improve chemical resistance, but it isknown to be difficult to make cross-linked capstocks thin enough toreplace a painted finish.

U.S. Pat. Nos. 5,975,625, and 6,852,405 describes automotive vehiclebodies having a single layer plastic outer body and an inner metalframe.

Problem/Solution

There is a desire for a thin capstock material that has a very highgloss, and has a high impact resistance, where the high gloss resistsgloss reduction damage caused by surface contacts with chemicals such asisopropyl alcohol, ethyl alcohol, methyl alcohol, sulphuric acid,phosphoric acid, toluene, isooctane, diisobutylene, and chemicalmixtures such as gasoline fuel, diesel fuel, bio-fuel, bitumen,antifreeze, brake fluid, engine oil, Pancreatin (bird feces substitute),tree resin, and sunscreen. The high gloss finish should also be easilyrestored to within 10% of the initial surface gloss.

It has surprisingly been found that a thin high gloss surface layer overa high-impact resistance interior layer, can be provided that willminimize the gloss reduction, and enable easy restoration of the highgloss finish to within 10% of the original gloss.

Further advantages of the invention over traditional high gloss paint(used over an undercoating) in automotive applications include reductionof manufacturing steps and elimination of volatile organic solventsassociated with coatings.

The multi-layer structure of the invention can pass an 85° C. exposuretest, and should be cost competitive with traditional high gloss paint.

Further, while it is difficult to handle and process a typicalcross-linked capstock where the cross-linking occurs during thepolymerization, a post-polymerization reaction can be used to formuseful cross-linking, such as by irradiation such as UV radiation ande-beam radiation.

SUMMARY OF THE INVENTION

In a first aspect, the invention relates to a multi-layer polymerstructure comprising a thin, high gloss outer cap layer having a 60°gloss of greater than 80, preferably greater than 85, and morepreferably greater than 90, as measured by a BYK Gardner Micro-Tri-Gloss20/60/85 degree Gloss Meter, wherein said cap layer has a thickness offrom 0.01 mm to 0.8 mm, preferably 0.0127 mm to 0.65 mm, and morepreferably from 0.04 mm to 0.38 mm; and an internal high impactresistant layer, wherein said high impact layer has an ASTM D256 notchedIzod result at 23° C. of greater than 0.8 ft-lb/in, preferably greaterthan 1.0 ft-lb/in, and more preferably greater than 1.2 ft-lb/in.

In a second aspect, the thin high gloss outer cap layer of the firstaspect has a heat deflection temperature (HDT), as measured by ASTM D648(1.8 MPa) of at least 175° F., when prior to measurement, the samplesare annealed at 80° C. for 96 hours then slow-cooled over 4 hours to 23°C.

In a third aspect, the thin, high gloss outer cap layer of any of thefirst two aspects, contains, as the matrix, at least one acrylic and/orstyrenic polymer.

In a fourth aspect, the multi-layer polymer structure of any of theprevious aspects, contains, in the thin, high gloss outer cap layer,less than 5 weight percent, preferably less than 3 weight percent,preferably less than 1 weight percent, and most preferably no impactmodifiers.

In a fifth aspect, the thin, high gloss outer cap layer of any of theprevious aspects is chemical resistant and scratch resistant, and has agloss retention of over 85%, preferably over 90% and a delta E of lessthan 5, preferably less than 3 for each test material using thefollowing procedure: for 6×6 inch samples conditioned at 85° C. for onehour and rubbed with ten back-and-forth strokes with a PIG Hazmat padsoaked with a test chemical, then wiped with a clean PIG Hazmat pad,washed, and reconditioned for at least one hour, and 60° glossre-measured. The test chemicals for the rub are chemicals such asbutylene glycol and glyceryl stearate typically found in sunscreens. Thecloths used in the test may be 3″×14″ PIG Hazmat Pads (MAT302) or 3″×14″PIG Hazmat Pads (MAT423).

In a sixth aspect, the thin, high gloss outer cap layer of any of theprevious aspects contains a polymer having a weight average molecularweight of at least 70,000 g/mol.

In a seventh aspect, the internal high impact resistant layer of any ofthe previous aspects, is a thermoset, thermoplastic, and/or a polymercomposite.

In an eighth aspect, the internal high impact resistant layer of any ofthe previous aspects has as a matrix polymer a thermoplastic selectedfrom the group consisting of acrylonitrile butyl styrene (ABS) polyvinylchloride (PVC), and high impact polystyrene (HIPS), polycarbonate (PC),a blend of acrylic polymer and polylactic acid, impact modifiedacrylics, impact modified styrenics, polycarbonate, thermoplasticpolyolefin (TPO), polyamides, polyimides, polyesters, polyurethanes,polyolefins and blends thereof.

In a ninth aspect, the high-impact layer of any of the previous aspectsis a composite composition containing particles, nanoparticles, and/orfibers.

In a tenth aspect, the composite composition of any of the previousaspects is a fiber-reinforced acrylic composite, said composite formedfrom a blend of one or more acrylic polymers with one or more acrylicmonomers that are impregnated into said fibers, followed bypolymerization.

In an eleventh aspect, the multi-layer structure of any of the previousaspects further comprises a tie layer or adhesive layer between theexterior high gloss layer, and interior high impact layer.

In a twelfth aspect, the multi-layer structure of any of the previousaspects exists over a substrate, wherein said substrate is selected frommetal; ceramics; and cellulosics; thermoplastic, elastomeric, andthermoset polymers having a thickness in the range 0.1 mm to 30 mm andpreferably 1.0 mm to 5 mm.

In a thirteenth aspect, the multi-layer structure of any of the previousaspects comprises two high gloss outer cap layers, one on either side ofthe internal high impact resistant layer.

In a fourteenth aspect, a method for restoring the gloss on a chemicallyor physically marred polymer multi-layer structure of any of theprevious aspects is presented, where the method includes the step ofremoving or hiding the mar.

In a fifteenth aspect, the method of aspect 14, involves the marrestoration through the process of buffing, polishing, wiping, chemicaltreating, and/or sanding said multi-layer structure, wherein said glossis restored to within 30%, preferably 20%, and most preferably within10% of the original gloss, as measured by a BYK Gardner Micro-Tri-Gloss20/60/85 degree Gloss Meter,

In a sixteenth aspect, the multi-layer polymeric structure of any of theprevious aspects, is manufactured by thermoforming, in-mold decorating,sequential injection molding, coextrusion, resin transfer molding within-mold decoration, or 3D printing (additive manufacturing).

In a seventeenth aspect, an article is presented which contains the thinmulti-layer polymeric structure of any of the previous aspects, wherethe article is selected from the group consisting of exterior paneling,automotive body panels, automotive body trim, recreational vehicle bodypanels or trims, exterior panels for recreational sporting equipment,marine equipment, exterior panels for outdoor lawn, garden andagricultural equipment and exterior paneling for marine, aerospacestructures, aircraft, public transportation applications, interiorpaneling applications, interior automotive trims, interior panels formarine equipment, interior panels for aerospace and aircraft, interiorpanels for public transportation applications, and paneling forappliances, furniture, and cabinets.

DETAILED DESCRIPTION OF THE INVENTION

“Copolymer” as used herein, means a polymer having two or more differentmonomer units. “Polymer” is used to mean both homopolymer andcopolymers. For example, as used herein, “PMMA” and “polymethylmethacrylate” are used to connote both the homopolymer and copolymers,unless specifically noted otherwise. (Meth)acrylate is used to connoteboth acrylates and methacrylates, as well as mixtures of these. Polymersmay be straight chain, branched, star, comb, block, or any otherstructure. The polymers may be homogeneous, heterogeneous, and may havea gradient distribution of co-monomer units. All references cited areincorporated herein by reference.

As used herein, unless otherwise described, percent shall mean weightpercent. Molecular weight is a weight average molecular weight asmeasured by GPC. In cases where the polymer contains some cross-linking,and GPC cannot be applied due to an insoluble polymer fraction, solublefraction/gel fraction or soluble fraction molecular weight afterextraction from gel is used.

“Multi-layer” as used herein describes a structure having at least twolayers attached directly or indirectly to each other, wherein theexterior layer is a high-gloss capstock, and at least one interior layeris a high impact layer. The layers may be directly in contact with eachother, or may contain one or more other layers in between, such as a tielayer, an adhesive layer, a vapor barrier, a color layer or specialeffects layer, etc. In one embodiment, the multi-layer structure has ahigh gloss capstock on either side of the interior high impact layer.This arrangement is especially useful where the multilayer structure istransparent or translucent, and the surfaces of both sides would bevisible.

Exterior, High Gloss Layer

The exterior high gloss layer is an acrylic- and/or styrenic-basedlayer; is chemical resistant, mar resistant and scratch resistant, withany deterioration of the high gloss being restorable to within 10% ofthe original gloss. The 60° gloss of the exterior layer is greater than80, preferably greater than 85, and more preferably greater than 90, asmeasured by a BYK Gardner Micro-Tri-Gloss 20/60/85 degree Gloss Meter.

The exterior, high gloss layer may optionally contain 0.01-20 wt %nano-sized particles additives to improve the chemical resistance, marresistance, scratch resistance, and/or improve the ability of the highgloss surface to be restored after incurring damage from chemicalexposure, marring, and/or scratching. Useful nano-sized inorganicfillers include, but are not limited to silica, alumina, zinc oxide,barium oxide, molybdenum disulfide, boron nitride, tungsten disulfide,titanium oxide, nanographene, nanographite, graphite nanoplatelets, andgraphite oxide nanoparticles.

The exterior, high gloss layer is thin, having a thickness of from 0.01mm to 0.8 mm, preferably 0.0127 mm to 0.65 mm, and more preferably from0.04 mm to 0.38 mm.

The exterior, high gloss layer has a heat deflection temperature (HDT),of greater than 175° F. (or 80° C.) as measured by ASTM D648 (1.8 MPa),when samples are annealed at 60-80° C. for 96 hours then slow-cooledover 4 hours to 23° C.

The acrylic or styrenic polymer of the invention has a weight averagemolecular weight of between 50,000 and 500,000 g/mol, and preferablyfrom 70,000 and 200,000 g/mol, as measured by gel permeationchromatography. The molecular weight distribution of the acrylic polymermay be monomodal, or multimodal with a polydispersity index greater than1.5. Copolymers containing comonomers that will lower the HDT of thecopolymer, such as C₁₋₆ acrylates, should have a weight averagemolecular weight of greater than 100,000 g/mol. In a preferredembodiment, an acrylic cap layer will contain predominately methylmethacrylate monomer units, and have less than 10 weight percent, andpreferably less than 5 weight percent of comonomers. The acryliccapstock may also have comonomers such as methacrylic acid, tertiobutylcyclohexanol methacrylate, alpha-methyl styrene, and other T_(g)increasing monomers, where the total co-monomer content can be up to25%.

In one embodiment the cap layer is a blend of an acrylic or styrenicpolymer with up to 90 weight percent, preferably less than 60 weightpercent, more preferably less than 35 weight percent % of polyvinylidenefluoride (PVDF) homopolymers or copolymers. A blend of acrylic polymerswith less than 30 weight percent, preferably less than 20 weight percentof polylactic acid can also be used. The high gloss acrylic capstock canalso be a crosslinked acrylic sheet with less than 5% crosslinkingagent.

In one embodiment, the exterior, high-gloss layer may be a polymerblend, containing the acrylic or styrenic polymer plus up to 60 wt %,preferably up to 40 wt % of one or more other compatible, miscible orsemi-miscible polymers. One useful blend is a blend of apoly(meth)acrylic polymer or copolymer withacrylonitrile-styrene-acrylate (ASA) polymer.

In one embodiment, crosslinking is provided by a post-polymerizationreaction, such as by the use of irradiation. Useful irradiation includesUV radiation, gamma radiation and e-beam. By using a post-polymerizationcross-linking mechanism, a thinner cap layer that is easily processablecan be achieved.

“Acrylic polymer” as used herein is meant to include polymers,copolymers and terpolymers formed from alkyl methacrylate and alkylacrylate monomers, and mixtures thereof. The alkyl methacrylate monomeris preferably methyl methacrylate, which may make up from 50 to 100percent of the monomer mixture. 0 to 50 percent of other acrylate andmethacrylate monomers or other ethylenically unsaturated monomers,included but not limited to, styrene, alpha methyl styrene,acrylonitrile, and crosslinkers at low levels may also be present in themonomer mixture. Other methacrylate and acrylate monomers useful in themonomer mixture include, but are not limited to, methyl acrylate, ethylacrylate and ethyl methacrylate, butyl acrylate and butyl methacrylate,iso-octyl methacrylate and acrylate, n-octyl acrylate, lauryl acrylateand lauryl methacrylate, stearyl acrylate and stearyl methacrylate,isobornyl acrylate and methacrylate, methoxy ethyl acrylate andmethacrylate, 2-ethoxy ethyl acrylate and methacrylate, isodecylacrylate and methacrylate, tertiobutyl cyclohexyl acrylate andmethacrylate, tertiobutyl cyclohexanol methacrylate, trimethylcyclohexyl acrylate and methacrylate, methoxy polyethylene glycolmethacrylate and acrylate with 2-11 ethylene glycol units, penoxyethylacrylate and methacrylate, alkoxylated phenol acrylate, ethoxylatedphenyl acrylate and methacrylate, epoxypropyl methacrylate,tetrahydrofurfuryl acrylate and methacrylate, alkoxylatedtetrahydrofurfuryl acrylate, cyclic trimethylolpropane formal acrylate,carprolactone acrylate, dimethylamino ethyl acrylate and methacrylatemonomers. Alkyl (meth) acrylic acids such as methacrylic acid andacrylic acid or C1-C8 esters thereof can be useful for the monomermixture. Alkyl (meth) acrylic acids such as methacrylic acid and acrylicacid can be useful for the monomer mixture. Most preferably the acrylicpolymer is a copolymer having 85 99.5 weight percent of methylmethacrylate units and from 0.5 to 15 weight percent of one or more C₁₋₈straight or branched alkyl acrylate units.

Styrenic-based polymers include, but are not limited to, polystyrene,high-impact polystyrene (HIPS), acrylonitrile-butadiene-styrene (ABS)copolymers, acrylonitrile-styrene-acrylate (ASA) copolymers, styreneacrylonitrile (SAN) copolymers, methacrylate-butadiene-styrene (MBS)copolymers, styrene-butadiene copolymers, styrene-butadiene-styreneblock (SBS) copolymers and their partially or fully hydrogenenatedderivatives, styrene-isoprene copolymers, styrene-isoprene-styrene (SIS)block copolymers and their partially or fully hydrogenenatedderivatives, and styrene-(meth)acrylate copolymers such asstyrene-methyl methacrylate copolymers (S/MMA). A preferred styrenicpolymer is ASA. The styrenic polymers of the invention can bemanufactured by means known in the art, including emulsionpolymerization, solution polymerization, and suspension polymerization.Styrenic copolymers of the invention have a styrene content of at least10 percent by weight, preferably at least 25 percent by weight.

The capstock should contain less than 15 weight percent impact modifier,preferably less than 5 weight percent, more preferably less than 3weight percent and most preferably less than 1 weight percent. In onepreferred embodiment, the cap layer contains no impact modifier.

Interior High Impact Layer

The thin multi-layer paneling structure of the invention has at leastone high impact resistant interior layer. This could be animpact-resistant thermoplastic, a blend of thermoplastics where theblend demonstrates impact-resistance, a blend of one or morethermoplastics and one or more thermoplastic elastomers and/orthermoplastic vulcanizates where the blend demonstratesimpact-resistance, a thermoset polymer or a polymer composite. The highimpact layer has an ASTM D256 notched Izod result at 23° C. of greaterthan 0.8 ft-lb/in, preferably greater than 1.0 ft-lb/in, and morepreferably greater than 1.2 ft-lb/in.

Useful high impact resistant thermoplastics include, but are not limitedto, acrylonitrile butyl styrene (ABS) polyvinyl chloride (PVC), and highimpact polystyrene (HIPS), polycarbonate (PC), a blend of acrylicpolymer and polylactic acid, impact modified acrylics such as RNEW® fromArkema, impact modified styrenics, polycarbonate, thermoplasticpolyolefin (TPO), poly(phenylene oxide), polyphenylene ether,polystyrene polyamides, polyimides, polyesters, polyolefins and blendsthereof. Preferred thermoplastics are ABS and polycarbonate.

Useful composites include, but are not limited to, thermoplastic andthermoset resins that are reinforced with particles or nanoparticlesincluding but not limited to graphite, carbon nanotubes, and silica;and/or reinforced with fibers, including but not limited to glassfibers, carbon fibers, and natural fibers. The particles and/ornanoparticles may have a mechanical modulus greater than or less thanthe continuous phase. The fibers could be in the form of individualfibers, braided fibers, and woven or non-woven mats. Thermoplasticcomposites include those with a matrix of ABS, PVC, HIPS, acrylicpolymers, polyamides, polyurethanes, styrenics, polyether ketone ketone,and polyether ether ketone. Useful thermoset matrices include, but arenot limited to polyesters or epoxies.

In one embodiment, a composite is formed using an acrylic liquid resinsystem containing a blend of acrylic monomer, acrylic polymer and aninitiator. The liquid resin system is used to impregnate fibers,followed by polymerization. ELIUM® resins from Arkema are a usefulexample of such a system.

In one embodiment, the interior high impact resistant polymer is a blendof an acrylic resin and a polyester, such as a polylactic acid.

The thickness of the entire multi-layer structure depends on the finalapplication of that structure, but is typically in the range of 0.1 mmto 30 mm and preferably 1.0 mm to 5 mm.

Manufacturing

The multi-layer structure of the invention may be manufactured byseveral different means, as known in the art. The structure could beformed by coextrusion, extrusion lamination, extrusion coating, in-molddecoration, sequential injection molding, thermo-forming of aco-extruded sheet or cast sheet, RTM-TS (resin transfer molding within-mold decoration), and 3D printing (additive manufacturing).

Properties

The thin multi-layer structure of the invention has several propertiesthat make it especially useful in many application.

The high gloss cap has a 60° gloss of greater than 80, preferablygreater than 85, and more preferably greater than 90, as measured by aBYK Gardner Micro-Tri-Gloss 20/60/85 degree Gloss Meter.

The high gloss cap is resistant to chemicals, marring, scratching,crazing, and color shift, as well as to gloss reduction. The mostsignificant appearance change after surface chemical exposure for opaquecolored samples is gloss reduction, which is used in the currentinvention to characterize the chemical damage and success ofrestoration.

The gloss of the high gloss cap can be easily restorable should damageoccur. Since the cap layer is thicker than a typical coating, there isadditional material to remove in order to restore the surface aesthetic.It can be restored by polishing, which cannot be achieved with a paintedsurface. Other means to facilitate restoration include, but are notlimited to buffing, wiping, chemical treatment, and/or sanding.

The structure could be transparent or translucent, which is not possiblefor a painted automobile or other type of panel.

Applications/Uses

The multi-layer structure of the invention, because of its excellentgloss, mar and scratch resistance, and the ability to restore the gloss,is an excellent material for use in many applications and articles.These include, but are not limited to internal and exterior paneling,automotive body panels, auto body trim, recreational vehicle body panelsor trims, exterior panels for recreational sporting equipment, marineequipment, exterior panels for outdoor lawn, garden and agriculturalequipment and exterior paneling for marine, aerospace structures,aircraft, public transportation applications, interior panelingapplications, interior automotive trims, interior panels for marineequipment, interior panels for aerospace and aircraft, interior panelsfor public transportation applications, and paneling for appliances,furniture, and cabinets.

Within this specification embodiments have been described in a way whichenables a clear and concise specification to be written, but it isintended and will be appreciated that embodiments may be variouslycombined or separated without parting from the invention. For example,it will be appreciated that all preferred features described herein areapplicable to all aspects of the invention described herein.

EXAMPLES Chemical Resistance Test Method

Chemicals such as butylene glycol and glyceryl stearate typically foundin sunscreens are applied to plastic surfaces in this test. The highgloss acrylic capstock surfaces are exposed to sunscreen chemicals at85° C. for 30 minutes and 24 hours. The detailed test method is asfollows: For 6×6 inch samples conditioned at 85° C. for one hour andrubbed with ten back-and-forth strokes with a PIG Hazmat pad soaked witha test chemical, then wiped with a clean PIG Hazmat pad, washed, andreconditioned for at least one hour, and 60° gloss re-measured. The testchemicals for the rub are a mixture of butylene glycol and glycerylstearate typically found in sunscreens. The cloths used in the test maybe 3″×14″ PIG Hazmat Pads (MAT302) or 3″×14″ PIG Hazmat Pads (MAT423).

After the chemical exposure at the designated temperatures, the sampleswere cooled down and stabilized at room temperature for an hour beforebeing washed with de-ionized water and wiped clean. The starting surfacegloss and final surface gloss are characterized by a BYK GardnerMicro-Tri-Gloss 20/60/85 degree Gloss Meter and the 60° is recorded(measured parallel to the rubbing direction). The measurement unitconforms to the standards DIN 67530, ISO 2813, ASTM D 523 and BS 3900Part D 5. Values reported are the percentage of surface gloss that isretained after chemical exposure.

Buffing Method

The high gloss acrylic surface is buffed and polished with the followingmethod. Apply tallow and rouge to a cotton muslin buffing wheel. Buffsample for 30-240 seconds with light pressure below the axis of thewheel; enough pressure to let the wheel graze the surface of the sample.Following the buffing step, apply light pressure on sample with a cottonflannel polishing wheel for 10 seconds to further smooth out thesurface. After buffing and polishing, clean the acrylic surface withsoap and water and dry with cotton cloth.

Scratching Test Method

The high gloss acrylic surface is scratched according to the followingmethod. A 6″×6″ injection molded high gloss acrylic plaque isconditioned at 50±5% relative humidity at 23±1° C. for 48 hours. Then,the surface is scratched by a spherical asperity having a radius ofcurvature of 1±0.1 mm and 15 N scratch load on a Taber multi-fingerscratch tester Model 710. The scratching speed is 100±5 mm/s and thelength of the scratch is 140 mm.

Paper Polishing Method

Samples exposed to scratching damaged were paper polished within 1 hourafter scratching by the following method. A 4″×4″ polishing paper (3M™281 Q Wetordry™ 2 micron polishing paper) was wrapped around a densesponge. Using light pressure and a circular polishing motion, thescratched acrylic surface was polished by hand with the polishing papercontinuously for 5 minutes. After paper polishing the acrylic surfacewas washed with soap and water and dried with cotton cloth. The 20surface gloss of a non-scratched region of the plaque was measuredbefore and after paper polishing with a BYK Gardner Micro-Tri-Gloss20/60/85 degree Gloss Meter as previously described.

Scratch Visibility Analysis

The visibility of scratch damage is quantified by an optical microscopymethod. A digital image of the scratched region of the surface iscaptured in bright-field mode with a Nikon ME600 optical microscopeequipped with a Pixelink PL-D 685 color camera at 100× magnification.The image is converted to an RGB color format, where each pixel color isexpressed by R, G and B values (integer values 0 to 255) for the Red,Green and Blue components of the pixel color, according to the RGB colorsystem. Then, the R, G and B values are measured for each pixel withintwo analysis regions of identical size and dimensions, A and B. Region Ais entirely contained within the scratched region, and region B isadjacent to Region A and entirely contained within the non-scratchedregion. Both regions must contain an area greater than 1000 pixels. Foreach region, the average R, G, and B values of all pixels arecalculated. Finally, the Scratch Visibility Value is calculatedaccording to:

Scratch Visibility Value=|[(R _(A) +G _(A) +B _(A))/3]−[(R _(B) +G _(B)+B _(B))/3]|

Where R_(A), G_(A) and B_(A) are the average Red, Green and Blue colorvalues, respectively, of all pixels in Region A. Likewise, R_(B), G_(B)and B_(B) are the average Red, Green and Blue color values,respectively, of all pixels in Region B. It follows that scratchvisibility increases with increasing Scratch Visibility Value.

Example 1 Gloss Restoration after Chemical Exposure Damage

Chemicals such as butylene glycol and glyceryl stearate typically foundin sunscreens can cause significant damage to acrylic materials at hightemperatures (85° C.), This Example demonstrates the removal of surfacedamages and/or surface residue and the restoration of surface gloss andcolor. Table 1 shows the gloss retention before and after 30±10 secondsof buffing. The acrylic materials were exposed to a sunscreen thatcontains a mixture of butylene glycol and glyceryl stearate as maincomponent at 85° C. for 24 hours before buffing, using the chemicalresistance test method described above. After the initial 30±10 secondsof buffing, the surface gloss of the high gloss acrylic capstock can berestored to as high as 80% of the original 60° surface gloss. To restorethe high gloss surface to 90% of the original gloss, repeated buffingwas carried out as illustrated in Table 2, where 2 minutes of totalbuffing time can restore the gloss to within 10% of the original gloss.

TABLE 1 Gloss Retention After Chemical Exposure Damage, Before and After30 ± 10 seconds Buffing (samples are exposed to 85° C. for 24 hours,sunscreen) After chemical Original Gloss resistance Test, Injectionmolded (60°) before Buffing After Buffing Sample 1 90.2 10.4% 70.3%Sample 2 89.7 39.0% 80.9% Sample 3 87.6 26.6% 72.7% Sample 4 91.4 32.2%58.9% Sample 5 86.6 4.62% 58.5% Sample 1 = clear PMMA/EA copolymerhaving an EA comonomer content of 1-10 wt % and a weight averagemolecular weight in the range of 70,000 to 110,000 g/mol. Sample 2 =clear PMMA/EA copolymer having an EA comonomer content of 1-10 wt % anda weight average molecular weight in the range of 100,000 to 200,000g/mol. Sample 3 = clear PMMA/EA copolymer having an EA comonomer contentof 1-10 wt % and a weight average molecular weight in the range of70,000 to 110,000 g/mol, with 10-35 wt % of impact modifier based on theweight of the PMMA/EA copolymer. Sample 4 = clear PMMA/EA copolymerhaving an EA comonomer content of 1-10 wt % and a weight averagemolecular weight in the range of 70,000 to 110,000 g/mol, with 30-60 wt% of impact modifier based on the weight of the PMMA/EA copolymer.Sample 5 = black PMMA/EA copolymer having an EA comonomer content of 0.1to 2.0 wt % and a weight average molecular weight in the range of 70,000to 110,000 g/mol, with 0.5 to 15 wt % of impact modifier base on theweight of the PMMA/EA copolymer.

TABLE 2 Change in Gloss of Sample 3 with Repeat Buffing Total Time(minutes) Gloss (60°) Gloss Retention 0 4.8 5.54% 0.5 50.3 58.1% 1.064.7 74.7% 2.0 80.5 93.0% 3.0 79.6 91.9% 4.0 80.8 93.3%

Example 2: Chemical Resistance Test

Samples of acrylic capstocks were exposed to sunscreen at 85° C.according to the chemical resistance test method described.

Sample 6 is a black PMMA/EA copolymer having an EA comonomer content of0.1 to 2.0-wt % and a weight average molecular weight in the range of70,000 to 110,000 g/mol,Sample 7 is a black PMMA/MAA copolymer (having a MAA comonomer contentof 1-10 wt % and a weight average molecular weight in the range of70,000 to 110,000 g/mol),Both samples are tested in duplicates, and both samples exhibit morethan 90% gloss retention and minimal color change (delta E less than 3),as shown in Table 3.

TABLE 3 Initial Gloss Gloss After Exposure 60° Gloss Sample (60°) (60°)Retention Delta E 6 86.4 90.7 104.9% 2.16 6 86.1 92.8 107.8% 2.48 7 87.285.5 98.1% 0.44 7 87.6 85.9 98.1% 0.41

Example 3: Surface Restoration after Scratch Damage

Exterior paneling often incurs surface damage due to scratching andabrasion. This example demonstrates the utility of scratch resistantformulations such as those described in WO 18132818 A3 for the exteriorlayer of high gloss exterior paneling. Also demonstrated is therestoration of a surface after scratching damage via paper polishing.6″×6″ samples plaques were prepared by injection molding and thenaffixed to steel plates for scratch tests and paper polishing. Sampleswere subjected to scratching according to the scratching test methoddescribed above, and then paper polished according to the paperpolishing method described above. The scratch visibility, as well assurface gloss before and after paper polishing are listed in Table 4.

Sample 8 is a black PMMA/EA copolymer having an EA comonomer content of0.1 to 2.0 wt % and a weight average molecular weight in the range of70,000 to 110,000 g/mol.Sample 9 is the same as Sample 8, with the addition of 15 wt % of CabotCAB-O-SIL® TS622 fumed silica. Sample 9 was prepared by melt compoundingthe black PMMA/EA copolymer and Cabot CAB-O-SIL® TS622 fumed silica on a27 mm Leistritz ZSE-27HP twin-screw extruder.The initial gloss of Sample 8 and Sample 9 were above 85 points for 60°gloss and above 78 points for 20° gloss, despite the presence ofnanoparticle reinforcement in Sample 9. After scratching, the scratchvisibility of Sample 8 (38.1) was significantly greater than Sample 9(5.6). Visually, the scratch visibility of Sample 8 also appeared moresevere than Sample 9. After paper polishing, the gloss of both Sample 8and 9 reduced, however the gloss retention of sample 9 (98%) was greaterthan sample 8 (76%). The scratch visibility after paper polishingreduced for both samples, with the greatest reduction for sample 8.Sample 8 demonstrated relatively low 20° gloss retention after paperpolishing (76%). Sample 9 demonstrated the useful combination of highinitial gloss, low scratch visibility both before and after paperpolishing, as well as excellent (98%) 20° gloss retention after paperpolishing.

Gloss Scratch Scratch after 20° Visibility Visibility Initial PaperGloss Value Before Value Sample Gloss Polishing Re- Paper After Paper ID(20°/60°) (20°/60°) tention Polishing Polishing Sample 8 79.9/86.560.4/78.9 76% 38.1 4.7 Sample 9 78.3/85.2 76.4/83.4 98% 5.6 3.2

With low heat buildup colorants such as IR reflective pigments or IRtransmitting organic dyes, the heat buildup (temperature rise of plasticabove ambient) of dark acrylic capstocks can be reduced as much as 30°F. (determined using ASTM D4803). Accordingly, the service temperatureof exterior paneling with IR reflective pigments or IR transmittingorganic dyes will be much lower than the service temperature of exteriorpaneling without IR reflective pigments nor IR transmitting organicdyes. The lower service temperature may improve chemical resistance byreducing the thermodynamic free energy of mixing between the polymericexterior paneling and the chemical to which the polymer substrate isexposed. It follows that the lower service temperature may significantlyreduce the penetration of chemicals into the exterior paneling, deferthe potential degradation caused by these chemicals, and reduces thetemperature differences between the layers within the exterior paneling,which may be a multilayer structure, to minimize the possibility of adelamination failure within the exterior paneling. Lower servicetemperature may also reduce the temperature difference between theexterior paneling and any supporting material to which the exteriorpanel may be adhered, such as metal, to minimize the possibility ofdelamination failure of the adhesive interface.

What is claimed is:
 1. A multi-layer polymer structure comprising: a. athin, high gloss outer polymeric cap layer, having a 60° gloss ofgreater than 80, preferably greater than 85, and more preferably greaterthan 90, as measured by a BYK Gardner Micro-Tri-Gloss 20/60/85 degreeGloss Meter, wherein said cap layer has a thickness of from 0.01 mm to0.8 mm, preferably 0.0127 mm to 0.65 mm, and more preferably from 0.04mm to 0.38 mm; and b. an internal high impact resistant layer, whereinsaid high impact layer has an ASTM D256 notched Izod result at 23° C. ofgreater than 0.8 ft-lb/in, preferably greater than 1.0 ft-lb/in, andmore preferably greater than 1.3 ft-lb/in.
 2. The multi-layer polymerstructure of claim 1, wherein said thin, high gloss outer polymeric caplayer has a heat deflection temperature (HDT), as measured by ASTM D648(1.8 MPa) of at least 175° F., when prior to measurement, the samplesare annealed at 80° C. for 96 hours then slow-cooled over 4 hours to 23°C.
 3. The multi-layer polymer structure of claim 1, wherein said thin,high gloss outer polymeric cap layer comprises as the matrix polymer atleast one acrylic and/or styrenic polymer.
 4. The multi-layer polymerstructure of claim 1, wherein said thin, high gloss outer cap layercontains less than 5 weight percent, preferably less than 3 weightpercent, preferably less than 1 weight percent, and most preferably noimpact modifiers.
 5. The multi-layer polymer structure of claim 1,wherein said thin, high-gloss outer polymeric layer further comprises0-20 weight percent, preferably 10-15 weight percent nanoparticles. 6.The multi-layer polymer structure of claim 5, wherein said nanoparticlesare selected from the group consisting of silica, alumina, zinc oxide,barium oxide, molybdenum disulfide, boron nitride, tungsten disulfide,titanium oxide, Nanographene, nanographite, graphite nanoplatelets, andgraphite oxide nanoparticles.
 7. The multi-layer polymer structure ofclaim 1, wherein said thin, high gloss outer polymeric cap layer ischemical resistant and scratch resistant, having a gloss retention ofover 85%, preferably over 90% and a delta E of less than 5, preferablyless than 3 for each test material according to following procedure: for6×6 inch samples conditioned at 85° C. for one hour and rubbed with tenback-and-forth strokes with each test material then wiped, washed, andreconditioned for at least one hour, and 60° gloss re-measured, the testmaterials for the rub being done with chemicals such as butylene glycoland glyceryl stearate typically found in sunscreens; soaked into a cloththat is a 3″×14″ PIG Hazmat Pad (MAT302).
 8. The multi-layer polymerstructure of claim 1, wherein the polymer of said thin, high gloss outerpolymeric cap layer has a weight average molecular weight of at least70,000 g/mol.
 9. The multi-layer polymer structure of claim 1, whereinsaid internal high impact resistant layer, is a thermoset,thermoplastic, and/or a polymer composite.
 10. The multi-layer polymerstructure of claim 1, wherein said internal high impact resistant layer,comprises a thermoplastic selected from the group consisting ofacrylonitrile butyl styrene (ABS) polyvinyl chloride (PVC), and highimpact polystyrene (HIPS), polycarbonate (PC), a blend of acrylicpolymer and polylactic acid, impact modified acrylics, impact modifiedstyrenics, polycarbonate, thermoplastic polyolefin (TPO), polyamides,polyimides, polyurethanes, polyesters, polyolefins and blends thereof.11. The multi-layer polymer structure of claim 10, wherein saidhigh-impact layer is a composite composition containing particles,nanoparticles, and/or fibers.
 12. The multi-layer polymer structure ofclaim 11, wherein said composite composition is a fiber-reinforcedacrylic composite, said composite formed from a blend of one or moreacrylic polymers with one or more acrylic monomers that are impregnatedinto said fibers, followed by polymerization.
 13. The multi-layerpolymer structure of claim 1, wherein said structure further comprises atie layer or adhesive layer between the exterior high gloss layer, andinterior high impact layer.
 14. A multi-layer polymer structure,comprising said thin multi-layer structure of claim 1 over a substrate,wherein said substrate is selected from the group consisting of metal;ceramics; cellulosics; thermoplastic, elastomeric, and thermosetpolymers having a thickness in the range 0.1 mm to 30 mm and preferably1.0 mm to 5 mm.
 15. The multi-layer polymer structure of claim 1,wherein said structure comprises two high gloss outer cap layers, one oneither side of the internal high impact resistant layer.
 16. A methodfor restoring the gloss on a chemically or physically marred multi-layerpolymer structure of claim 1, wherein said method includes the step ofremoving or hiding the mar.
 17. The method of claim 15, wherein said maris restored through the process of buffing, polishing, wiping, chemicaltreating, and/or sanding said multi-layer structure, wherein said glossis restored to within 30%, preferably 20%, and most preferably within10% of the original gloss, as measured by a BYK Gardner Micro-Tri-Gloss20/60/85 degree Gloss Meter,
 18. The multi-layer polymeric structure ofclaim 1, wherein said structure is manufactured by thermoforming,in-mold decorating, sequential injection molding, coextrusion, resintransfer molding with in-mold decoration, or 3D printing (additivemanufacturing).
 19. An article comprising the multi-layer polymericstructure of claim 1, wherein said article is selected from the groupconsisting of exterior paneling, automotive body panels, autobody trim,recreational vehicle body panels or trims, exterior panels forrecreational sporting equipment, marine equipment, exterior panels foroutdoor lawn, garden and agricultural equipment and exterior panelingfor marine, aerospace structures, aircraft, public transportationapplications, interior paneling applications, interior automotive trims,interior panels for marine equipment, interior panels for aerospace andaircraft, interior panels for public transportation applications, andpaneling for appliances, furniture, and cabinets.